Sometimes it is desired to deploy sensor arrays on the floor of an ocean or similar body of water. These arrays will often have structure wherein a plurality of sensors is fastened to a cable. To deploy the array, the cable is paid out from the fantail of a ship traveling at bare steerageway.
For arrays of this structure, it can be very difficult to deploy and recover the array without damaging some of the sensors, and deployment of the array via a mechanical means can prove to be challenging. This is because the tension of the cable varies due to the pitch and roll of the ship and because of the allowable bend radius of the cable at the connection points with the sensors. If the tension is too great, the cable may part. In some cases, array deployment is achieved either by tensioning the cable by hand or by not at tensioning at all. Recovery can be achieved either by hand or with the assistance of friction provided by the groove space between two tires in tandem, which are powered by a hydraulic motor. In the latter case, the cable rides over the rotating groove and tension is maintained by hand on the inboard side of the tandem of tires.
Deployment and recovery of long sections of cable by hand is extremely exhausting. The friction afforded by the tandem tire groove is often inadequate as cable that has been in the sea for some time often has gelatinous marine growth on it that causes the cable to be very slippery. Also, the tension can also often become excessive if the cable gets wedged between the tires and begins to wrap around; excessive tension risks parting of the cable or damage to the sensors as the array is being deployed or recovered. Alternatively, rollers could be used as a mechanical means for deployment or retrieval of an array. But rollers produce the equivalent of a speed bump when a sensor passes therethrough, which is also potentially very damaging to both the sensor and to the cable due to the limitations of allowable bend radius at the location where the cable connects to the sensor.
In view of the above, it is an object of the present invention to provide a shipboard winch having guide vanes for maintaining adequate spacing between multiple wraps of cable with sensors. Another object of the present invention is to provide a shipboard winch having guide vanes wherein the array cable is wrapped around two rotating drums in figure eight fashion to prevent twisting of the cable and thus prevent “hockles” while applying a controlled tension on the array of sensors for deployment of the array from the deck of a ship without damaging the array. It is yet another object of the present invention to provide a shipboard winch having guide vanes that allows for recovery of the array without damage to the array sensors. Another object of the present invention is to provide a shipboard winch that deploys and recovers cables in a manner that places a constant tension on the cable during recovery, even if the cable has become fouled with marine growth. Still another object of the present invention is to provide a winch for deploying/recovering a cable from ocean without causing twists or hockles in the array cable.